A method for large-scale preparation of Cu4 nanoclusters and their application in Ag + Applications in detection

Abstract

This invention discloses a method for the large-scale preparation of Cu4 nanoclusters and their application in Ag. + Applications in detection. This invention uses cuprous chloride as the copper source and, under the protection of organophosphorus ligands, prepares large quantities of Cu4 nanoclusters with precise structures. The preparation process is simple, time-efficient, and allows for large-scale production. This method overcomes the limitations of traditional nanocluster yields, scaling up the reaction volume by 30 times compared to basic methods, achieving a yield of ~6 grams in a simple one-pot process. Furthermore, these nanoclusters exhibit superior luminescence properties and can detect Ag. + With its unique selective response, the mass production method of this material makes its industrial production possible.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterial preparation technology, specifically relating to a method for the large-scale preparation of luminescent Cu4 nanoclusters and their application in Ag. + Applications in detection. Background Technology

[0002] In recent decades, the preparation and application of nanoclusters have been a hot topic of research. Compared with bulk materials, when the size of materials is reduced to the nanoscale, many superior physical and chemical properties are produced (Arabin Journal of Chemistry, 2019, Vol. 12, pp. 3096-3107). Nanoclusters are members of the material family composed of inorganic metal cations and organic ligands, and they have broad application prospects in catalysis (Journal of the American Chemical Society, 2021, Vol. 143, pp. 12100-12107), drug delivery (Biomaterials, 2021, Vol. 273, Document No.: 120846), and sensing (Biosensors and Bioelectronics, 2017, Vol. 89, pp. 666-672). Based on these excellent properties, the synthesis methods of atomically precise metal nanoclusters have been developed unprecedentedly, and hundreds of atomically precise metal nanoclusters have been reported to date. However, most clusters currently have extremely low yields, and their synthesis steps are cumbersome and time-consuming, which greatly limits the development of atomically precise metal nanoclusters in various fields.

[0003] Due to silver ions (Ag) + Ag has wide applications in industrial consumer products such as electronics (Applied Clay Science, 2017, Vol. 146, pp. 449-456), pharmaceutical engineering (Journal of Photochemistry and Photobiology B: Biology, 2020, Vol. 202, Document No.: 11706), and biosensing (Frontiers in Chemistry, 2020, Vol. 8, Document No.: 601621). However, Ag... + Excessive use has led to excessive emissions of Ag into the environment. + Its inherently difficult-to-degrade biological characteristics make it easily accumulate in the human body through various pathways, while also causing ecological pollution (Journal of Geochemical Exploration, 2019, Vol. 200, pp. 159-166). For example, Ag... +It can eliminate enzyme activity (Regulatory Toxicology and Pharmacology, 2018, Vol. 98, pp. 257-267), bind to proteins or amino acids and render them inactive (Environmental and Experimental Botany, 2021, Vol. 186, Document No.: 104458), etc. A method for efficiently and rapidly detecting Ag has been developed. + Detection methods for Ag are essential. Currently, relevant Ag detection methods already exist. + The detection methods have been reported in literature and patents. For example, Xu et al. published a one-pot synthesis method for carbon quantum dots to detect Ag. + (Spectrochimica Acta Part A - Molecular and Biomolecular Spectroscopy, 2019, Vol. 208, pp. 162-171), Kaur et al. reported on the silane receptor-based Ag... + The recognition performance (New Journal of Chemistey, 2019, Vol. 43, pp. 5525-5530) has the following related patents: (1) Application No.: CN201710093905.1, title: Application of a phthalocyanine-iridium metal complex in silver ion detection, which has been granted; (2) Application title: Application of a phthalocyanine-iridium metal complex in silver ion detection, which has entered the substantive examination stage.

[0004] As can be seen from the above description and examples, firstly, establishing a method for the efficient and large-scale preparation of atomically precise metal nanoclusters is key to advancing their applications in catalysis, biomedicine, and other fields. Secondly, current research on atomically precise metal nanoclusters mainly focuses on the development of new material structures and the exploration of formation mechanisms; research on ion detection of atomically precise metal nanoclusters is relatively limited. This invention covers a method for the efficient and large-scale preparation of Cu4 nanoclusters and its detection of Ag. + Selective detection. Summary of the Invention

[0005] The purpose of this invention is to provide an efficient and large-scale preparation method for Cu4 nanoclusters, and their application in Ag... + Applications in detection.

[0006] The Cu4 nanoclusters of this invention have the molecular formula [Cu4H(PPh2Py)4Cl2](BPh4).

[0007] The present invention also provides a method for preparing the Cu4 nanoclusters, comprising the following steps:

[0008] Dissolve 50 mg of cuprous chloride in 15 mL of methanol, add 200 mg of diphenyl-2-pyridinium phosphine, and stir vigorously. After 15-20 min, add 120 mg of borane-tert-butylamine complex (BH3·C4H) while stirring. 11 The solution gradually turned yellow. After 1 hour, stirring was stopped, and 2 mL of a methanol solution of sodium tetraphenylborate (50 mg) was added. After standing for a period of time, the solution was centrifuged. The precipitate was washed several times with methanol to remove excess ligands and byproducts, which yielded pure [Cu4H(PPh2Py)4Cl2](BPh4) nanoclusters.

[0009] In the above reaction process, cuprous chloride is the copper source, diphenyl-2-pyridinium phosphine is the ligand, borane-tert-butylamine complex is the reducing agent, and sodium tetraphenylborate is the counterion.

[0010] Large-scale preparation method:

[0011] Based on the above-mentioned basic synthesis method, the product can be successfully obtained by scaling up the synthesis by 10, 20, and 30 times.

[0012] Taking the 30-fold synthesis method as an example, 6 g of diphenyl-2-pyridinium phosphine was added to 180 mL of a methanol solution of cuprous chloride (1.5 g), and the mixture was stirred vigorously at room temperature. After 30 min, 3.6 g of tert-butylborane complex was added to the mixture. After 5 h, the stirring was stopped, and 10 mL of a methanol solution of tetraphenylborate sodium (1.5 g) was mixed with the reaction solution. The mixture was centrifuged, and the pale yellow precipitate was washed several times with normal methanol to remove excess ligands and byproducts, yielding ~5.86 g of pure clusters.

[0013] The application of the Cu4 nanoclusters of this invention is the preparation of detection reagents using the Cu4 nanoclusters for Ag. + Response detection.

[0014] For Ag + The responsiveness test method included: ten metals were selected, namely anhydrous calcium chloride (CaCl2, 96%), cobalt chloride hexahydrate (CoCl2·6H2O, 99%), copper chloride dihydrate (CuCl2·2H2O, 99%), nickel nitrate hexahydrate (Ni(NO3)2·6H2O, 98%), manganese chloride (MnCl2, 99%), magnesium chloride (MgCl2, 99%), sodium chloride (NaCl, 99.5%), silver nitrate (AgNO3, 99.8%), ferric chloride hexahydrate (FeCl3·6H2O, 99%), ferrous sulfate monohydrate (FeSO4·H2O, 98%), and zinc nitrate hexahydrate (Zn(NO3)2·6H2O, 99%), and a 1 mM aqueous solution was prepared with distilled water for the detection of ion responsiveness.

[0015] The specific operating steps are as follows:

[0016] 0.12 g of Cu₄ nanoclusters were dissolved in 60 mL of dimethyl sulfoxide (2 mg / mL) as a standard solution. 2 mL of the standard solution and 1 mL of deionized water were placed in a standard quartz tube as blank controls. Then, 1 mL of different ion solutions were added to 2 mL of the standard solution for fluorescence detection. The fluorescence detection method for silver ions was the same as the ion selection method. A certain volume of Ag₂ was added... + The solution was added to 2 mL of standard solution, diluted to 3 mL with distilled water, and the fluorescence quenching spectrum was recorded. All fluorescence detection procedures were performed at room temperature.

[0017] All the metal salts mentioned are of analytical grade.

[0018] The different ionic solutions mentioned above are various metal salt solutions prepared using distilled water as a solvent;

[0019] The ultraviolet spectrophotometer mentioned is the UV-6000PC ultraviolet spectrophotometer;

[0020] The fluorescence spectrophotometer mentioned is an Omnifluo990LSP fluorescence spectrophotometer.

[0021] This invention utilizes cuprous chloride as the copper source to prepare large quantities of Cu4 nanoclusters with precise structures under the protection of organophosphorus ligands. The preparation process is simple, time-efficient, and allows for large-scale production. This method overcomes the limitations of traditional nanocluster yields, scaling up the reaction volume by 30 times compared to basic methods, achieving a yield of approximately 6 grams in a simple one-pot process. Furthermore, these nanoclusters exhibit superior luminescence properties and can react with Ag... + With its unique selective response, the mass production method of this material makes its industrial production possible. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the atomic structure of the copper-based nanoclusters of the present invention;

[0023] Figure 2 The images show the product obtained after being prepared by magnification 30 times in Example 1, and the mass of the purified product weighed on an electronic balance.

[0024] Figure 3 The images show the ultraviolet and fluorescence spectra of the nanoclusters of this invention (the inset is a fluorescence photograph of the material);

[0025] Figure 4 The fluorescence spectra of the nanoclusters of this invention responding to different metal ions of the same concentration are shown.

[0026] Figure 5This is a bar chart showing the response of the nanoclusters of the present invention to different metal ions of the same concentration;

[0027] Figure 6 The present invention relates to nanoclusters for different concentrations of Ag. + The responsive fluorescence spectrum;

[0028] Figure 7 The maximum fluorescence intensity of the nanoclusters of this invention at the fluorescence excitation site is related to Ag. + Linear relationship curve of concentration. Detailed Implementation

[0029] The present invention will be specifically described below with reference to the embodiments:

[0030] Example 1: Preparation of Cu4 nanoclusters

[0031] Basic preparation procedure: First, weigh 50 mg of cuprous chloride and dissolve it in 15 mL of methanol. Under stirring, add 200 mg of diphenyl-2-pyridinium phosphine to the above solution and continue stirring. After 15-20 min, add 120 mg of tert-butylborane complex. After 1 h, stop stirring, weigh 50 mg of sodium tetraphenylborate and dissolve it in 2 mL of methanol to form a solution, add it to the above reaction mixture, let it stand for a period of time, centrifuge, discard the supernatant, and obtain a yellow precipitate. Continue washing with methanol / n-hexane to remove excess ligands and byproducts, and then recrystallize with dichloromethane / n-hexane at room temperature. After 2-3 days, yellow blocky crystals are obtained, which is the target product.

[0032] Large-scale preparation scheme: Taking a 30x scale-up as an example, 6g of diphenyl-2-pyridinium phosphine was weighed and added to 180mL of methanol solution containing 1.5g of cuprous chloride. The mixture was stirred vigorously at room temperature for 30min, followed by the addition of 3.6g of tert-butylborane complex. The reaction was continued for 5h, then stirring was stopped. 10mL of sodium tetraphenylborate methanol solution (0.15g) was mixed with the reaction solution and centrifuged. Subsequent processing was performed as described above. Finally, based on Cu atom conversion yield, approximately 5.86g of pure clusters were obtained in a yield of about 90%.

[0033] Figure 1 The atomic structure diagram of the cluster obtained in Example 1, measured using an X-ray single-crystal diffractometer, shows that the main structure contains a tetrahedral core composed of four copper atoms, and the average distance between the Cu atoms is... Secondly, a hydrogen atom is located at the center of this tetrahedron, forming a whole with Cu4 through H-Cu coordination (Cu4H). Finally, the Cu4H core is protected by four phosphine ligands and two Cl atoms, anchored to the cluster surface through P-Cu, N-Cu, and Cl-Cu coordination, respectively, with average bond lengths as follows: and Note: The blue spheres are copper atoms, the green spheres are chlorine atoms, the red spheres are phosphorus atoms, the light blue spheres are nitrogen atoms, the gray spheres are carbon atoms, the white spheres are hydrogen atoms, the pink spheres are boron atoms, and the light green spheres are chlorine atoms.

[0034] Figure 2 The images show photographs of the product obtained after preparation by magnification 30 times in Example 1, and the mass of the product weighed on an electronic balance after purification.

[0035] Figure 3 The images show the ultraviolet absorption spectrum of the nanoclusters prepared in Example 1 dissolved in dichloromethane, and the fluorescence emission spectrum of the material obtained by exciting the dichloromethane solution with a wavelength of 390 nm. The photographs in the images are optical photographs of the material dissolved in dichloromethane solvent under natural light and ultraviolet light, as well as optical photographs of the material in its solid state under natural light and ultraviolet light.

[0036] Example 2: Fluorescent nanoclusters on Ag + Response experiment

[0037] For Ag + The responsiveness test method included: ten metals were selected, namely anhydrous calcium chloride (CaCl2, 96%), cobalt chloride hexahydrate (CoCl2·6H2O, 99%), copper chloride dihydrate (CuCl2·2H2O, 99%), nickel nitrate hexahydrate (Ni(NO3)2·6H2O, 98%), manganese chloride (MnCl2, 99%), magnesium chloride (MgCl2, 99%), sodium chloride (NaCl, 99.5%), silver nitrate (AgNO3, 99.8%), ferric chloride hexahydrate (FeCl3·6H2O, 99%), ferrous sulfate monohydrate (FeSO4·H2O, 98%), and zinc nitrate hexahydrate (Zn(NO3)2·6H2O, 99%), and a 1 mM aqueous solution was prepared with distilled water for the detection of ion responsiveness.

[0038] The specific operating steps are as follows:

[0039] 0.12 g of Cu₄ nanoclusters were dissolved in 60 mL of dimethyl sulfoxide (2 mg / mL) as a standard solution. 2 mL of the standard solution and 1 mL of deionized water were placed in a standard quartz tube as blank controls. Then, 1 mL of different ion solutions were added to 2 mL of the standard solution for fluorescence detection. The fluorescence detection method for silver ions was the same as the ion selection method. A certain volume of Ag₂ was added... + The solution was added to 2 mL of standard solution, diluted to 3 mL with distilled water, and the fluorescence quenching spectrum was recorded. All fluorescence detection procedures were performed at room temperature.

[0040] Figure 4 The fluorescence spectra of the nanoclusters in Example 2 for the response of different metal ions at the same concentration show that only Ag exhibits a response when different ions are added. + It showed a clear response to this, while the emission spectra of other ions did not change much.

[0041] Figure 5 The chart shows a comparison of absorbance at the maximum absorption wavelength of 550 nm (where I0 is the absorbance of the fluorescent material at 550 nm without any ionic solution, and I is the absorbance at 550 nm after adding different ions). It clearly shows that only Ag... + It exhibits a clear responsiveness to fluorescent materials.

[0042] Figure 6 For different concentrations of Ag + The fluorescence spectrum measured after adding the standard solution shows that as Ag... + As the concentration of Ag increases, the fluorescence intensity decreases. + It has a significant quenching effect on the fluorescence of this material.

[0043] Figure 7 To achieve the maximum fluorescence intensity at the maximum emission wavelength of 550 nm and Ag + The relationship between concentrations shows that it exhibits a linear correlation, and the detection limit is 9.8 μM.

Claims

1. A method for preparing Cu4 nanoclusters, characterized in that... Includes the following steps: Dissolve cuprous chloride in methanol, add diphenyl-2-pyridinium phosphine and stir. After 15-20 min of stirring, add the borane-tert-butylamine complex BH3·C4H3. 11 N, the solution gradually turns yellow. After 1 hour, stop stirring and add a methanol solution of sodium tetraphenylborate. After standing for a period of time, centrifuge. Wash the precipitate with methanol to remove excess ligands and byproducts to obtain pure Cu4 nanoclusters. The molecular formula of the Cu4 nanoclusters is [Cu4H(PPh2Py)4Cl2](BPh4).

2. The preparation method according to claim 1, characterized in that: The mass ratio of cuprous chloride, diphenyl-2-pyridinium phosphine, boron-tert-butylamine complex, and tetraphenylborate sodium is 5:20:12:

5.

3. The application of the Cu4 nanoclusters prepared by the method according to claim 1, characterized in that: Detection reagents were prepared using the Cu4 nanoclusters for Ag. + The application of responsive detection is for the purpose of non-disease diagnosis and treatment.

4. The application according to claim 3, characterized in that: The detection reagent is for Ag + The detection limit is 9.8 μM.

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